Electromagnetic control device



May 23, 1939. WEST 2,159,610

ELECTROMAGNET IG CONTROL DEVICE Filed Aug. 20, I937 ri f Fly. 4

IN V ENTOR.

RNEY.

pasted May 23, 1939 smc'rnomaonn'rro CONTROL DEVICE John D. West, Manitowoo, Wis., assignor to Manitowoc Shipbuilding .Corporation, Manitowoc,

Wis.

Application August 20, 1937, Serial No. 160,108 ,6 Claims. (01. 137-139) This invention relates to an electromagnetic;

controldevice. I Objects of this invention are to provide a dewhich is so constructed that-it maintains any selected pressure in a fluid pressure operated motor,'such, for example, as a bra ke cylinder,

1 the invention providing means whereby an operator remote from the device may set a rheostat or other controller at a selected point and an yelectromagnetic valve will maintain a .certain pressure in a brake cylinder or other device corresponding to the setting of the controller or rheostat, whereby the remote operator may accu- 1Qrately govern or control the pressure in the brake cylinder or other device with assurance that the apparatus will automatically maintain the pressure selected by the operator from his remote Jpoint without any further thought on the part 10f; :the operator, and whereby the operator may it vary this pressure, eitherdecreasingitor raising itas desired, the invention, however, in its broada electromagnetic valve interposed between the r operatorand the device actuated by fluid pressure. W I n greater detail, objects of this invention are tomprovide"electromagnetically controlled means forhmaintaining a definite pressure in a piston or other. pressure operated device, such, for ex-' ,of arheostat or other-control member determines thefamount of pressure maintained temporarily ,35 in' suchcylinder or other pressure operated del'vieei and to provide electromagnetic means which control a floating valvemovable to admit i orfexhaust fluid pressureto and from a cylinder I l or} other device and to cutoif communication x with such cylinder or other device, and to provide'ineans for unbalancingthe valve whereby the forceexerted by the valve is balanced against 1 the force exertedby the electromagneticdevice (so, that the valve floats approximately at its neu- 45 trai or cut-off position whereby it a'leak should 'occur inthe pressure system connected with the cylinder thejvalve will automatically restore the l pressureand when the pressure arrives at the desired 'point for which the electromagnetic de- 5 vicetis set, the valve will automatically cut off 5 further pressure fluid flow to the cylinder and reit ,yersely whereby iflthe pressure should for any 'j reason .increase, the valve will automatically 1 55 "der until the exact pressure for which the electrovice. which is adapted for remote control and,

est aspects not being limited to the control from :ra remote point but comprehending the automatic ample, as a brake cylinder, whereby the setting allow the escape of pressure fluid from the cylin- I magnetic device has been set is reached in the cylinder.

Further objects are to provide an electromagnetic device which is mechanically connected to a differential pressure controlling floating valve 'having a neutral cut-off position and having extreme positions on opposite sides thereof for admission and exhaust of pressure fluid to a pressure responsive device, such as a brake cylinder,

' for instance, and to so construct the apparatus that the electromagnetic device may have its pull or force controlled. from a remote point, as by means' of a controller or rheostat so that the operator .may from the remote point precisely determine the pressure that will exist in the cylinder, the device automatically maintaining this pressure without any further thought on the part of the operator. I

Further objects are to provide'a very simple construction although having the automatic features hereinabove enumerated, the invention specifically having for its object the provision of an ,electromagnetically operated. valvethat floats about its neutral position and accurately balances the magnetic pull of the valve against 2 the fluid pressure so that an automatic adjust- Figure 1 is a sectional elevation of theauto- U 'matic valve, withparts broken away.

Figure 2 'is a diagrammatic view of the valve in its association with a brake and a remote controller or rheostat.

Figure 3 is a transverse view showing the relative areas of the two portions of the differential valve.

Figure 4 is a fragmentary view showing a modified construction.

Referring to the-drawing, particularly Figure 2, l indicates a control board having a rheostat or controller 3 thereon. 2 is a brake dr-um whose operation it is desired to control from the controller, the controller it being understood being located at a remote point or else adjacent the apparatus, the device readily lending itself to remote control.

The controller 3 is con'nected'by means of the circuit 5 with the automatic valve In, a suitable sure, the direction of flow being indicated by the stem 44 extending upwardly from the core and passing through the aperture 41 of a fixed stop,

arrow 1 l, the exhaust by the arrow l2, and the arrows l3 and 14 indicating the flow either from or to the brake cylinder "5 by way of the pipe l5. In the form chosen for illustration, the brake cylinder I6 is so arranged that it relieves the pressure of the brake band 22 on the drum 2 when pressure fluid is admitted to the brake cylinder, the spring 33 applying the brake, such spring being coiled loosely about the rod 30 and bearing at one end against a fixed stop 34 and at the other end against a stop or shoulder 32 adjustably carried by the rod 30. The rod 30 is attached to the piston rod 31 so that as the piston rod moves to the right'in Figure 2, it compresses the spring, rocks the bell crank lever 28 in a counter-clockwise direction, and rocks the brake band lever 25 in a clockwise direction through the medium of the connecting link 21, the levers 25 and 28 being respectively pivoted as indicated at 26 and 29. The brake band 22 has a portion thereof spaced from the drum 2, as indicated, at 24, and attached to the brake lever 25.

' The other end of the brake band is indicated by the reference character 23 and is attached to a fixed support.

Referring to both Figures 1 and 2, it will be seen, as shown in- Figure 1, that the pipe I 5 leading to the brake cylinder communicates with the annular cavity I1 in the body of the valve, such body being indicated by the reference character l8 in Figure 1. i

The movable portion bf the valve, which constitutes the valve proper, is indicated by the reference character 59. It is controlled by means of a magnet which may take the form of a; s0- lenoid and which has a plunger 40 mechanically and adjustably connected with the valve 59 by means of the flexible wire or flexible rod 53, the details of the connection being hereinafter described.

The magnet chosen for illustration consists, as stated, of the solenoid type and the solenoid or winding is indicated by the reference character 39 and is housed within a casing or shell 38. The plunger or armature oi the magnet iscarried by the upper and lower springs M and 42 which are clamped to the plunger by means of the upper and lower clamping nuts 45 and 45'.

The core of the magnet does not have extensive motion and the springs will keep it from touching or dragging against the adjacent portion of the p is screwed upon the threaded stem 44 of the core and clamps the spring against a spacing sleeve, 43 carried by the core 40. If desired, this spacing sleeve 43 may be made of non-magnetic,

material, whereas, of course, the. core vis-"made of magnetic material, thus causing the core when the magnet is energized to have a tendency to rise. The springs 4i .and 42 are respectively housed in their casings 86 and 81 and downwardly opening vents 84 and 85 are provided.

The difierential valve has a relatively small upper head and a relatively larger lower head 68 and a reduced intermediate or waist portion 61. It is provided with a bore 58 that extends down to approximately its center of gravity which is approximately located at the point indicated by the reference character 50.

The enlarged lower head 68 has a cut off shoulder 16 which cuts off from the exhaust passage 18 and which constitutes the lower cut off shoulder of the differential valve. The upper head 65 has a cut off shoulder 13 for cutting off communication with the pressure fluid inlet 15, and constitutes the upper cut off shoulder of that differential valve. The passages 15 and 18 com municate' respectively with an annular pressur inlet port 14 and an annular exhaust port 11.,

The area of the upper head 66 is indicated i Figure 3 by the reference character 69 and its diameter by the reference character A in Figures 1 and 3. The diiference in area between the 'lower and upper heads 88 and 56 is indicated in Figure 3 by the reference character 10 and the diameter of the lower head 68 is indicated in Figures 1 and 3 by the reference character 13.

The differential valve, therefore, has a tendency to move downwardly to cut oil the pressure fluid and to open the exhaust. The .pull

of the solenoid is upwardly and is balanced which screws into the threaded aperture 52 of the valve. The valve is provided with a relatively smaller.aperture ti through which the wire 53 passes, emerging from this aperture at the point- 60, namely, at approximately the center of gravity of the valve. The upper portion of the flexible wire 53 extends through the opening 56 in the core 40 of the solenoid and its upper end is threaded and screws into a small nut 54, a lock nut 55 being provided. The nut 54 is clamped in place in the plunger by means of the set screw 51. It is thus readily possible to adjust the relative positions. of the solenoid plunger 40 and the differential valve 59.

A dash pot efiect is provided by providing the cavity 82 in a bottom cap 19 screwed into the bottom of the valve so that as the valve moves downwardly, air is compressed beneath the lower face '83 of the valve. It escapes through the restricted passage formed in the adjustable screw 8| which is screwed into the bottom of the cap 19. This prevents any shock from the operation of the valve and acts to prevent even instantaneous over shooting of the valve..

It is obvious that a rigid rod can be used in place of the flexible wire 53, provided suitable articulation is afforded at its upper and'lower ends. For example, as shown in the modified form of Figure 4, a rigid rod 88. connects the magnet plunger and the difierential valve, a

fragment of each being respectively indicated by the reference characters 9| and 92. which" the ends 101' the rod 88 b the respective, portions of the device is by pro viding upper and lower pins in the magnet core 9| and in the valve 92 whichpass through apertures 89 and 90 formed in the ends of the rigid rod 88. As indicated in Figure 4, these apertures may have transversely rounded surfaces to allow rocking in two directions at right angles to each other, to thus provide the requisite freedom at the ends of the rigid rod 88, suitable apertures 93 and 94 being provided in the plunger SI'andinthe valve 92. v I

The operation of the apparatus is as follows: The operator sets the rheostat or controller at the desired point and a certain definite force or pull is exerted by the solenoid. Thismoves the differential valve upwardly and allows fluid pressure to pass into the valve casing and into the 'brake cylinder until a pressure is built up within the brake cylinder and withinthe valve casing such that the pull on the differential valve opposes the pull of the solenoid sufliciently to move the valve downwardly, as viewed in Figure 1,- to

- cut-elf position. This action is wholly automatic.

If a leak should occur and the pressure should jfall, the valve will again adjust itself automatically so as to allow'the pressure to be builtup until the predetermined desired pressure for which the device is thenset is obtained. This v action is whollyautomatic and takes place with.-

\ sets the controller to allow less pull-to be exerted valve overcomes the pull ofthe solenoid and leak until the desired pressure is again by the solenoid and consequently 'thedifferential moves to exhaust position until the desired pressure is reached. Thereafter the solenoid justbalances the pull of the valve and the valve floats and moves back to cut-off or neutral position, where it stays unless a leak occurs. As described hereinabove, if a leak does occur, the valve automatically adjusts itself to compensate for the at. This action is automatic;

It will be seen, therefore,

operator sets the contr'oller'at the desired point,

' the valve automatically maintains this pressure the valve is not dependent upon the position of and floats at its neutral or cut-off position. Thus a floating electromagnetic valve has been provided which may be set from a remote point if desired'at anypressure wished for and which isthereafter wholly automatic in its action'in maintaining this pressure.

It is to be noted that the solenoid does not work against a spring and therefore does not balance its pull against a spring, but balances its pull against the desired fluid pressure within -the cavity I'I. Further it is to be noted that the valve is not dependent upon the position of the apparatus controlled by the valve, that is to .say,

the brake solenoid plunger 3|, but is dependent solely upon the balancing of the pull of the solenoid against the actual pressure existing within the cavity I l'within the valve casing, which is arrived that anelectromag- 1 netically controlled difierential v a1vehas=bee'n% provided which is so made that the valve may be controlled from a remote point and when the the same pressure as that existing in the brake cylinder i6.

-Wh ile the valve is described as a differential valve in which there is an over balancing, of ,pressure inj'one direction, it is to bedistinctly understood that other types of valves may beemployed without departing from the spirit of this invention. Further'it has .beenfound that by forming the valve in the manner indicated and connecting it withthe plunger of the sole-- noid in the flexible way as, described, the valve may beoperated without lubrication if desired. Further it is to" be noted that the dash pot chamber 82 is located on the other side of the,

exhaust port from the chamber ll. .Thus if any pressure fluid tends to leak, itwillnot pass. into 1,,

the clash pot but will arrive 'at the exhaust port ll first and consequently unwanted building up of pressure due to leaking of the valve, even after long servicefis prevented; A

The apertures 84 and 85 in the upper lower casings above and below the plunger of the sole.-

noid maybe made adjustable, as shown at 80 and 81, for the dash pot construction. In this i way it is possible to utilize the casings as dash pot chambers. However, it is usually preferred to mak e'the openings 84 and 85 of such size that there is no retardation due, totheseportions of. the apparatus.

1 It will be seen that anovel form of electrically controlled valve has been provided in which there is a precise-balancing between the pressurefurnished themotive member, such as the brake unit 'for instance, and the ,pull'of the solenoid thereby securing the automaticadjustment-of the valve to secure and maintain the desired pressure for which the operator has temporarily set the controller.

' It will be seen further that thepull ofthe.

solenoid is balanced against a force exactly proportional to and caused bythe fluid pressure; that if leaks occur, the valve ,will automatically adjust itself to maintain thepressure' at the.

desired point; and thatthis point at which the pressure is maintained may be controlled from,

a remote point or from an adjacent point by adjusting the controller.

Further it will be. seen that'the construction is such that if for anyreason the, electric line connecting the controller with the valve should be broken, neverthelessthe valve will automatically exhaust and allow the brake to close, thus affording maximumsafety. It-is to be'noted furtherthat noadjustment, of spring tension or othehtypes of adjustments of this general order are required for the valve;

but that theyalve automatically adjusts"itsc'elf, as'hereinabove described.

'While an electromagnet has been shown as i I the means for exerting a variable force on the difierential valve, it is obvious that other means could be employed, provided such means could exert a variable force which is exactly balanced by the pull of the valve. Also different forms of electromagnets could be employed, one form hav- .ing been chosen for the purpose of illustration. .Therefore, although this invention has been described in considerable detail, it is to be understood that such description is intended as'illus- 'trative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim: t

1. An electromagnetically controlled diiferen tial valve comprising ,a casing having a chamber 4 .i provided with-a delivery opening and having fluid-pressure inlet and outlet portsadapted to be selectively placed in communication with said chamber, an unbalanced differential valve controlling said ports and biased by: the fluid pres sure within said chamber towards exhaust positlon with the inlet port closed and the outlet port open and having'a neutral position closing both. ports; said differential valve occupying said neutral-position under both active and inactive conditions, and electromagnetic means urging said unbalanced differential valve in a direction in opposition to that towards which said valve is biased by. the fluid pressure in said chamber.

i munication with said inlet port or exhaust port,

2. An electromagnetic valve for controlling fluid pressure comprising a valve body portion having an inlet port and an exhaust portand having a chamber adapted to'be placed in comsaid valve including a movable valve. member normally occupying a neutral position with both the inlet portand the exhaust port closed, fluid pressure displacing means for displacing said valve member by fluid pressure within said chamber to open said exhaust port and maintain said inlet-port closed, and electromagnetic displacing means 'fo'r displacing said valve to open said inlet port and maintain said exhaust port closed,

said fluid pressureand electromagnetic dlsplac- 1 ixig means acting in opposite directions.

' 3. A differential electromagnetically controlled fluid pressure valve comprising a valve body portion having achamber provided with a. delivery opening and having an exhaust port and an inlet port, said valve including a differential piston normally occupying a neutral position with both ports closed and'adapt'edto slide in opposite directions to open the exhaust port andhold theinlet portjclosed, or to open the inlet port and hold'the exhaust port closed to thereby selectively connect said chamber with either said exhaust-port or saidinlet port, said difierential piston beirigj-isa cted upon by the fluidpressure within said ichamber'and tending to open the exhaust port whenvfluid pressure exists within said chamber, and electromagnetic means urging said differential piston in the opposite direction from that duezto fluid pressure within said chamber. v

4, An electromagnetic fluid pressureva1vecom ,prising a. valvefbody having an intermediate chamber provided 'with a delivery openingj and, having an exhaust port and an inlet port'on oppositesides of and adapted to be, selectively con-' nected with said intermediate chamber, said valve comprising a difl erential pis'ton, the larger part of which controls the exhaust port and the smallof said plunger.

aiisacro er part of which controls the inlet port, said valve having a normalneutral position with both the exhaust port andthe inlet port closed, and electromagnetic means tendlng to move the valve towards open position of the inlet port, whereby when said electromagnetic means is energized and fluid pressure supplied at the inlet port, said valve will float about its neutral position with the force due to the fluid pressure acting on the difierential piston balanced against the force due to the action of the electromagnetic means.

mal neutral position with both. the exhaust port and the'inlet port closed, and electromagnetic meanstending to move the valve towards open position of the inlet port, whereby when said electromagnetic means is energized and fluid pressure supplied at the inlet port, said valve will float about its neutral position with the force due to the fluid pressure acting on the difierential piston balanced against'the force due to the] action of the electromagnetic means, said piston when in neutral position under operating conditions'being acted upon solely, by the fluid pressure and the force exerted by said electromagnetic means.

6. An electromagnetic valve for controlling fluld pressure comprising a valve body portion having an inlet port and an exhaust port and havinga chamber adapted to be placed in communication with said inlet port or exhaust port,

said valve including a movable valve member normally occupying a neutral position with both the inlet portand the exhaust port closed-fluid pressure displacing means for displacing said .ivalve memberby fluid pressure within said chamber to open said exhaust port and maintain said inlet port closed, and electromagnetic displacing meansfor displacing said valve to open said inlet port and maintain said exhaust port closed, said fluid pressure and electromagnetic displacing meansacting lnopposite directions, said electromagneticg displacing meansincluding a sole noid and a plunger, said plunger being operatively connected to said movable valve member by means allowing said movable valve member-to align itself with saidbody portion independently J OHN' D. WEST. 

